collections - Component to iterate and render a nested tree-like object structure in JSF -

given class definition below:

public class comment {      string username;     string comment;     list<comment> replies;      // ... } 

is possible use construct jsf page renders data contained in comment instance in tree structure follows?

comments userone said blah blah ----     userthree replied     blah blah blah     ----     userthree replied     blah blah blah ---- usertwo said blah blah ---- userone said blah blah 

if nesting 1 level deep, or has fixed amount of maximum depth, nest jsf repeater components <ui:repeat> or <h:datatable> in each other usual way.

<ul>     <ui:repeat value="#{bean.comments}" var="comment">         <li>#{comment.username} #{comment.comment}             <ul>                 <ui:repeat value="#{comment.replies}" var="reply">                     <li>#{reply.username} #{reply.comment}</li>                 </ui:repeat>             </ul>         </li>     </ui:repeat> </ul> 

but if nesting level "unlimited", need jsf component instead can render tree hierarchy. not available in standard jsf component set. you'd need @ 3rd party component libraries primefaces <p:tree>, or richfaces <rich:tree>, or omnifaces <o:tree>. omnifaces 1 allows have full control on tree markup, while others you'd possibly need fiddle css want.

<o:tree value="#{bean.comments}" var="comment">     <o:treenode>         <ul>             <o:treenodeitem>                 <li>#{comment.username} #{comment.comment}                     <o:treeinsertchildren />                 </li>             </o:treenodeitem>         </ul>     </o:treenode> </o:tree> 

i'd clarity rename string comment property message or text orso.

if you're on jsf 2.x, consider <my:comments comment="#{bean.comments}"> composite component below.

<cc:interface componenttype="commentscomposite">     <cc:attribute name="comment" type="com.example.comment" required="true" /> </cc:interface> <cc:implementation>     <c:if test="#{not empty cc.comment.replies}">         <ul>             <c:foreach items="#{cc.comment.replies}" var="comment" varstatus="loop">                 <li>                     #{comment.username} #{comment.comment}                     <my:comments comment="#{cc.parent.comment.replies[loop.index]}" />                 </li>             </c:foreach>         </ul>     </c:if> </cc:implementation> 

@facescomponent("commentscomposite") public class commentscomposite extends uinamingcontainer {      private comment comment;      @override     public void setvalueexpression(string name, valueexpression expression) {         if ("comment".equals(name)) {             setcomment((comment) expression.getvalue(getfacescontext().getelcontext()));         }         else {             super.setvalueexpression(name, expression);         }     }      public comment getcomment() {         return comment;     }      public void setcomment(comment comment) {         this.comment = comment;     }  } 

see blog on subject, recursive tree of composite components.